28 June 2018
“While nuclear power offers attractive offsets to fossil fuel equivalents, nuclear power stations are not immune to regional and local climate change effects.”
In this piece by Aubrey R. Paris, Energy and Climate Scholar, NSF Graduate Research Fellow, and Ph.D. Candidate in the Department of Chemistry at Princeton University, and Matthew A. Rose, Department of Defense Strategic Planner and a recent graduate of the U.S. Army War College, we gain an new perspective on the relationship between nuclear power, the energy market, and climate change. Tim Nixon, Managing Editor, Thomson Reuters Sustainability.
If one’s goal is to generate large sums of carbon-free energy, pound for pound, nuclear power is one of the most attractive available technologies. The growing body of evidence indicating that anthropogenic activities are causing the increasing rate of climate change continues to nudge governments, markets, and industry toward carbon-reduced or carbon-free technologies. As such, nuclear power generation remains a vital component of global energy production and sustainability strategies (1). Yet somehow, nuclear energy is itself threatened by the very challenge it seeks to tackle: climate change.
Before unraveling this potential conflict, it is important to revisit how society reached a climate-dire scenario in the first place. Most climate projections and models rely heavily on carbon dioxide and other greenhouse gas emission levels to determine what a future climate could look like (2). Unfortunately for humankind, even moderate projections paint a starkly different climate landscape compared to today’s, and expected sea level rise and temperature increases pose significant threats to almost every globally connected system.
The goal of curbing greenhouse gas emissions (3) combined with noble intentions routinely edges “do-good” reformers toward easy and obvious solutions. Logically speaking, if reducing human-related greenhouse gas emissions will slow the rate of change, then investments in carbon-free technologies, like nuclear energy, should help. But this easy and obvious solution requires deeper scrutiny, and climate change is to blame.
While nuclear power offers attractive offsets to fossil fuel equivalents, nuclear power stations are not immune to regional and local climate change effects. Light water reactors, the most common type of nuclear generation facility, require cooling water sources to operate. Simply put, it’s all about water, and if the water source is inadequate, so is the power plant.
Considering this operating requirement, water availability and temperature fluctuations caused by climate change are likely to impact nuclear generation capacity. This is especially difficult to address because future trends in precipitation, water level, and temperature will differ according to region, causing plants in discrete parts of the United States—and world—to face their own water-related, climate-induced challenges. Using moderate climate projections, it is instructive to case-study geographically diverse facilities to assess how climate changes are likely to affect nuclear generation capacity.
As a first example, Millstone Power Station (Waterford, CT) and similar northeastern, coastal nuclear facilities will find excess water to be a challenge. This may initially sound counterintuitive, but what happens when inundation caused by unexpected or high-magnitude water flow prevents normal operation of power stations? By 2050, Connecticut will experience precipitation increases of 0.2–0.5 mm/day (4) and sea level rise of 0.2–1.7 ft (5). Under these conditions, Millstone Power Station will be at an elevated risk of damage due to storm surge, while flooding may prohibit facility access for personnel. This is particularly problematic considering the importance of safety-related access and evacuation points at nuclear facilities.
For completeness, it should be noted that the Nuclear Regulatory Commission (NRC)-granted licenses for Millstone’s two nuclear reactors expire in 2035 and 2045. However, license renewal is always possible and could even become probable if future energy needs require the facility’s doors to remain open.
On the other hand, the problems anticipated for Sequoyah and Watts Bar Nuclear Plants (Soddy-Daisy and Spring City, TN), whose current reactor licenses expire in 2020/2021 and 2035/2055, respectively, are nearly opposite those of Millstone. Tennessee should experience a 2–3 °C temperature increase by 2050 compared to the historical average (6), though this statistic could rise as high as 6 °C if carbon dioxide emissions are not drastically curbed (7). Summer drought frequency will increase by 65% in the same period, with no offsetting increases in summer water availability.
Since nuclear facilities’ major demand for water stems from a need to cool thermal loads, the temperature of incoming cooling water is critical for system efficiency. After its use, this water must be at a safe temperature to allow reintroduction into the environment (8). These factors aside, nuclear power plants must also compete with alternative water demands, particularly during times of water and heat stress.
Despite differences in future water availability, Millstone, Sequoyah, and Watts Bar nuclear facilities are at risk of temporary or permanent shut-downs, increasing in likelihood over time. At present, these three facilities alone power a total of four million homes in the United States, while simultaneously providing nearly 6,000 local jobs.
Furthermore, short- or long-term lapses in nuclear energy generation will likely require less-sustainable energy sources to fill the power gaps. Reasons for concern abound when considering the fact that 58 other nuclear power plants in the United States will suffer from their own regional climate challenges in the future, having similar impacts on energy, economy, and environment.
That said, it is important to note that energy is just one product that suffers when a plant reduces its operation. Nuclear plants also support the production of radioactive isotopes for medical and industrial purposes (9). Additionally, they produce tritium and other special nuclear material whose reduction could have national security implications (10).
Considering both the unprecedented rate of climate change and wide-reaching nature of anticipated impacts, achieving meaningful reductions in greenhouse gas emissions is paramount. When it comes to finding sustainable solutions to this complex problem, nuclear power sounds easy and obvious. But before doubling down on this particular solution, a more complete picture must be painted to portray all of climate change’s potential impacts on this apparent silver bullet. In the end, it may become clear that an easy and obvious solution does not exist.